Performance of natural polymer coagulants were studied for total dissolved solids removal from acid red dye. Response surface methodology (RSM) using face-centred central composite design (FCCD) optimized four variables of the coagulation-flocculation process including pH, coagulant dosage, dye concentration and time. Acidic solution pH increased the Total dissolved solid (TDS) removal efficiency. Accurate control of coagulant dosages gave optimum destabilization of charged particles and re-stabilization occurred at above 800mg/L dosages. Polymer performances were measured through time-dependent decrease in particle concentrations following aggregates growth. Charge neutralization, sweep flocculation and polymer adsorption were the active mechnisms in the coagulation-flocculation process. The verification experiments agreed with the predicted values with less than 4% standard error values. Overlay contour plot established an optimum condition for the multiple responses studied. The response surface methodological approach was appropriate for optimizing the coagulation-flocculation process while minimizing the number of experiments. Coagulants studied were highly effective in the TDS removal process.